[The assessment of regional cerebral blood flow using HMPAO-SPECT during depressive episode and in remission]

Twenty patients who met the DSM-IV criteria for major depressive disorder were investigated at rest using Single Photon Emission Computed Tomography (SPECT). Participation in the study required a minimum score of 18 points on the 17-item Hamilton Rating Scale. All patients were drug free for at least one week before the SPECT scan. Assessments were made twice during depression and after recovery. Regional tracer uptake was measured by a semiquantitative method. The reference region was delineated on the cerebellum. In remission a significant increase of 99m Tc-uptake in almost all regions of interest was observed what may point on the improvement of regional blood flow after recovery from depression. For most regions except right frontal and left parietooccipital there were no significant differences of tracer uptake between patients with bipolar and unipolar depression. The negative correlation between regional cerebral blood flow and Hamilton score was found in temporal areas and left temporo-parietal region. We did not find the influence of age on regional cerebral blood flow. In conclusion, during depression global reduction of brain metabolism was observed, which may point on the role of subcortical nuclei with diffuse cortical projection in pathogenesis of depression.